Pulverized-coal system



Sept. 6,1927.

J. E. BELL PULVERIZED boAL SYSTEM 3 Sheets-Sheet 2 Filed Aug- 22, 1923 IN VEN TOR Mm A TTOPNEYJ 2 mywn's Sept; 6, 1927. 1, 70

J. E. BELL- PULVERIZED COAL SYSTEM Fil ed Aug. 22 1923 3- Sheet S Sheet'IS A TTORNEYS Patented Sept. 6, 1927.

FHQE.

JOHN E. BELL, OF BROOKLYN, NEW YORK, ASSIGNOR TO COMBUSTION ENGINEERING CORPORATION, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

PULV'ERIZED-COAL SYSTEM.

Application filed August 22, 1928.

This invention has to do with the pulverization of material and its direct feed from the pulverizing apparatus to the point of use without intcrmmliarns such as storage bins. hoppers. screw conrerors. and the like. and it is especially usel'ul in connection with plants for the generation of steam from pulverized coal.

()ne of the great problems in the success' lul burning of pulverized fuel has been the obtaining of a uniform, even feed. to secure which, heretofore, rather conlplicated mechanism has been employed. It has been the practice in this art to pulvcrize the coal, lift the pulverized coal l'rom the. mill by an air blast to a cyclone se 'iarator which operates to separate the coal from the air, the. air being returned to the mill, and then to lead the pulverized coal. from the separator to a storage bin, from which it is fed by feeder n'iechanism to the pipes leading to the'burners of the furnace.

It is one of the primary objects of my invention to dispense with such complicated and expensive intermediary mechanism and to feed the coal directly from the mill to the furnaces, and in such manner that the coal is supplied uniformly and evenly, and also uniformly distributed even though a battery of furnaces is to be supplied from a single mill. In this connection I have'discovered that what is substantially a suction fan can be utilized as an effective distributor of pulverized material, particularly when such material is in some measure of suspension in air or other carrying medium or vehicle. How these and other objects incident to my invention are accomplished will be clear from the preferred form of the apparatus indicated in the drawings, in which:

Fig. 1 is a diagrammatic plan view of a battery of furnaces to which the pulverized coal is being supplied in accordance with my invention; Fig. 2 is asection taken on the line 22 of Fig. 1; and Fig. 3 is an enlarged sectional view of one of the distributor means, taken approximately on the line 3-3 of Fig. 1.

Referring now to the drawings, the reference letters A designate three boilers having suitable combustion chambers and evaporating surfaces, it being understood that the showing is of diagrammatic character. Each combustion chamber has in its arch or top wall, a plurality of burners 8, in this Serial No. 658,673.

instance four being shown For each co1nbuslion chamljier.

The coal, preferably crushed to a certain extent. is supplied to thc pulrerizingmill 9 by means ol the pipe ll). 'lhe pulverized coal is lalccn from the mill through the pipe ll by means of a shot ion l'an l2 lor removing the coal pneumalirallv or in suspension.

From the casing ol the fan 12 three dissymmetrically disposed and arranged discharge outlets l-l" from each of which a pipe 15 leads to one of the burners 8 of a setting. These fans uniformly distribute the coal to the pipes 15. The size, length and shapes of the pipes 15 are also such that the feed therethrough is approximately uniform; The burners are-also of uniform construction.

Sufficient air for carrying the coal to and through the burner nozzles is drawn through the mill 9, and the balance of the air for-combustion is supplied througlithc burners around the nozzles and also through the air inlets 16 in the-front wall of the combustion chamber, as is well understood in this art.

Referring now to Fig. 3, this. is a sectional view of the fan 12, the construction 'of'which may be, in effect, employed for the otherfans as well. The fan wheel. is indicated by the reference numeral 17 and is provided with a plurality of blades 18 which discharge the coal into the peripheral portion of the fan casing 19 laterally 'outwardly and somewhat upwardly for the reason that the fan wheel is disposed in the lower part of the casing andhas its bottom plate 20 inclining upwardly. This sets up somewhat of a swirling or vertical motion tending to prevent any accumulations. The peripheral portion of the casing is swelled out, as shown, to provide the discharge outlets 12.

From the foregoing it will be seen that the stream of pulverized coal from the mill is subdivided into substantially uniform secondary streams, each of which is subdivided into similar streams leading to the burners discharging directly into the interior of the combustion chamber. As a result of the substantially uniform construction and resistance of the several sets of pipes, the feed to all burners and to each furnace will be uniform and equal, the conditions between all of the corresponding parts of the system being uniform and equal for all practical purposes.

By preferably utilizing no more than the air required for properly carrying the pulverized coal from the mill to the burners,

the velocity of the entering streams of coal and air will not be so great as to produce eddying to an, objectionable extent or to otherwise interfere with the proper combustion of the coal in the combustion chamber. In this connection, the velocity of the entering streams should be such that the fuel and flame stream may be turned upwardly in a reverting or ,U-shaped course without forcible impingement on any of the refractories of the combustion chamber, while at the same time combustion is substantially completed within the chamber. By this arrangement theentering streams will have a velocity sufficiently greater than the velocity ace ate of the air induced through the burners and through the inlets 16 to produce that amount of eddying which is necessary to secure the degree of admixture required for prompt, complete and efieotive burning of the coal- Within thecombustion chambers.

It will be seen that the general arrange ment is such as to lend itself to quite a variation in the number and disposition of the boilers; and thatit is possible, if desired, to use mills in multiple for a single unit, so that one mill may be cut out for repairs, if needed.

What I claim is:

In combination with a pulverized fuel system having a mill and a furnace, a diS- charge pipe from the mill, a fan adapt-ed to draw fuel in suspension therethrough, a conduit adapted to receive and convey fuel discharged from said fan, a plurality of feeders between said conduit and the furnace and adapted to deliver to a plurality of points of use in said furance, and a .fan interposed between said conduit and. said feeders and adapted to receive fuel in suspension from the conduit and distribute it to the feeders through uniformly peripherally disposed discharge openings. y

In testimon whereof, I have hereunto signed my name.

JOHN E. BELL. 

